Integrated production of hydrogen and methane in a dairy biorefinery using anaerobic digestion: Scale-up, economic and risk analyses.

Anaerobic digestion has emerged as the most appealing waste management strategy in biorefineries. Particularly, recent studies have highlighted the energy advantages of waste co-digestion in industrial biorefineries and the use of two-stage systems. However, there are some concerns about moving the system from laboratory testing to industrial scale. One of them is the high level of investment that is required. Therefore, this study carried out a techno-economic analysis (scale-up and energy production, economic and risk analysis, and factorial design) to assess the feasibility of single- and two-stage systems in the treatment of cheese whey and glycerin for the production of hydrogen and methane. Scenarios (S1 to S9) considered thermophilic and mesophilic single and two-stage systems with different applied organic loading rates (OLRA). The analyses of scale-up and energy production revealed that S3 (a thermophilic single-stage system operated at high OLRA 17.3 kg-COD.m-3.d-1) and S9 (a thermophilic-mesophilic two-stage system operated at high OLRA 134.8 kg-COD.m-3.d-1 and 20.5 kg-COD.m-3.d-1, respectively) were more compact and required lower initial investment compared to other scenarios. The risk analysis performed by a Monte Carlo simulation showed low investment risks (10 and 11%) for S3 and S9, respectively, being the electricity sales price, the key determining factor to define whether the project in the baseline scenario will result in profit or loss. Lastly, the factorial design revealed that while the net present value (NPV) is positively impacted by rising inflation and electricity sales price, it is negatively impacted by rising capitalization rate. Such assessments assist in making decisions regarding which system can be fully implemented, the best market circumstances for the investment, and how market changes may favorably or unfavorably affect the NPV and the internal rate of return (IRR).

Transfer of ß-lactam and tetracycline antibiotics from spiked bovine milk to Dambo-type cheese, whey, and whey powder.

The aim of this study was to investigate the transfer of residues of five ß-lactam antibiotics (ampicillin, penicillin G, cloxacillin, dicloxacillin and cephalexin) and two tetracyclines (tetracycline and oxytetracycline) in the processing of cheese and whey powder, evaluating the effect of the processes and the final concentration in each product generated. Raw milk was fortified at two concentration levels with the seven antibiotics. The first concentration level (C1) was chosen according to the maximum residue limit (MRL) of each antibiotic (ampicillin and penicillin G: 4 µg kg-1; cloxacillin and dicloxacillin: 30 µg kg-1; cephalexin, tetracycline and oxytetracycline: 100 µg kg-1). The second concentration level (C2) was spiked as follows according to each antibiotic: 0.5 MRL (cloxacillin, dicloxacillin, cephalexin), 0.1 MRL (tetracycline and oxytetracycline) and 3 MRL (ampicillin and penicillin G). The antibiotics were analyzed by LC-MS/MS. No ampicillin or penicillin G residues were found in cheese or whey powder, although they were detected in whey at concentrations similar to those added to raw milk. Cephalexin was mostly distributed in whey between 82% and 96%, being the antibiotic that presented the highest concentration in whey powder (784 ± 98 µg kg-1) when milk was spiked at the MRL. The whey distribution of cloxacillin and dicloxacillin ranged from 57% to 59% for cloxacillin and from 46% to 48% for dicloxacillin, and both concentrated in whey powder. Tetracyclines were the antibiotics that concentrated in cheese, with retentions between 75% and 80% for oxytetracycline and between 83% and 87% for tetracycline. The distribution of antibiotics in the dissimilar stages of the cheese and whey powder production processes, as well as their concentration in the final products, depend on each type of antibiotic. Knowledge of the transfer of antibiotic residues during the process and final disposal is an input for the risk assessment of their consumption.

Galactooligosaccharides: Physiological benefits, production strategies, and industrial application.

The concern for better life quality has been encouraging the bioprocess industries to develop technological strategies to obtain new biomolecules. Galactooligosaccharides (GOS) are an important class of food-grade oligosaccharides, being classified as non-digestible, and which present prebiotic potential, promoting better conditions of health and well-being. The main benefits include the selective stimulation of beneficial microorganisms, the decrease in the formation of toxic compounds, the increase in the absorption of minerals, improvement of an immune response, and a reduction in the severity of obesity and diabetes. This review approaches the recent methodologies and strategies to obtain GOS, their health benefits, purification, and technological properties for industrial application. Improvements in the process are continuously being investigated, with the technique of enzyme immobilization representing a potentially promising strategy. Sustainable GOS productions have been reported by the use of agro-industrial residues, such as cheese whey. Despite these advances, the main concern of the process consists in the low yield, which implies high investments in the purification of the bioproducts. Technological and nutritional approaches to the GOS application in different industrial sectors are also reported.

Cell permeabilization of Kluyveromyces and Saccharomyces species to obtain potential biocatalysts for lactose hydrolysis

Yeast's beta-galactosidase is an intracellular enzyme, through which it is possible to determine in vivo its activity as a biocatalyst in the lactose hydrolysis. Permeabilization process was used for transforming the microorganisms cells into biocatalysts with an enhanced enzyme activity. The potential application of this enzyme technology in industrial process depends mainly on the enzyme activity. Beta-galactosidase enzyme that hydrolyzes lactose, for instance, is largely dependent on the reaction time and its stability under different physical conditions, such as pH, temperature and enzyme concentration. The objective of this study was to optimize the cellular permeabilization process of Kluyveromyces marxianusCCT 3172 and Saccharomyces fragilisCCT 7586 cultured in cheese whey for lactose hydrolysis. Box-Behnken design was carried out for cell permeabilization with three independent variables, ethanol concentration, permeabilization time and temperature. The best permeability conditions for K. marxianusCCT 3172 were 27% (v v-1) ethanol, 3 min at 20ºC, with specific enzymatic activity of 0.98 U mg-1.For S. fragilisCCT 7586, a specific enzymatic activity of 1.31 U mg-1was achieved using 45% (v v-1) of ethanol, 17 min. of reaction under 17ºC. Thus, it was concluded that cellular permeabilization with ethanolis an efficient process to determine beta-galactosidase activity.(AU)

Spray-Dried Microcapsules of Cheese Whey and Whey Permeate as a Strategy to Protect Chia Oil from Oxidative Degradation.

Research background: Cheese whey and whey permeate are dairy industry by-products usually sent to effluent treatment or incorrectly disposed in the environment, generating costs for the production of dairy products and environmental problems due to the high organic load. Cheese whey and whey permeate can be reused as wall materials to form chia oil microcapsules, which act as a barrier to prooxidants. This study aims to develop an encapsulation method by spray-drying to protect chia oil using dairy by-products as wall materials. Experimental approach: We evaluated cheese whey, whey permeate and mixtures of m(cheese whey):m(whey permeate)=50, 70 and 80% as encapsulating agents with the spray-drying process. Initially, we characterized the chia oil and encapsulating materials. Chia oil emulsions were prepared using the encapsulating materials and an emulsifier. The stability of the emulsions was evaluated by creaming index, and they were characterized according to size distribution and polydispersity index. Emulsions were encapsulated in a spray dryer with inlet and outlet air temperature at 125 and 105 °C, respectively. After encapsulation, we assessed the oxidative degradation of chia oil over 30 days of storage by determining the peroxide index. Results and conclusions: Emulsions presented creaming index between 51 and 83% in all formulations, and the oxidative stability of microencapsulated chia oil was significantly higher than that of free chia oil after 30 days. Wall material combination affected both encapsulation efficiency and oxidation protection. The cheese whey and whey permeate (8:2) mixture exhibited the highest encapsulation efficiency (70.07%) and ability to protect the chia seed oil. After 30 days, the peroxide value was below the maximum limit considered safe for human consumption. Novelty and scientific contribution: According to these results, dairy by-products can be used for encapsulation of oxidation-sensitive oils. This represents an alternative use for dairy by-products, which otherwise are discarded and can impact the environment due to their high organic load. Our findings suggest that dairy by-products can be effectively used as wall materials to generate value-added products.

Lactic acid production using cheese whey based medium in a stirred tank reactor by a ccpA mutant of Lacticaseibacillus casei.

In lactobacilli, CcpA is known to modulate the expression of genes involved in sugar metabolism, stress response and aerobic adaptation. This study aimed to evaluate a ccpA mutant of Lacticaseibacillus casei BL23 to increase lactic acid production using cheese whey. The ccpA derivative (BL71) showed better growth than the L. casei wild-type in the whey medium. In a stirred tank reactor, at 48 h, lactate production by BL71 was eightfold higher than that by BL23. In batch fermentations, the final values reached were 44.23 g L-1 for BL71 and 27.58 g L-1 for BL23. Due to a decrease in the delay of lactate production in the mutant, lactate productivity increased from 0.17 g (L.h)-1 with BL23 to 0.80 g (L.h)-1 with BL71. We found that CcpA would play additional roles in nitrogen metabolism by the regulation of the proteolytic system. BL71 displayed higher activity of the PepX, PepQ and PrtP enzymes than BL23. Analysis of prtP expression confirmed this deregulation in BL71. Promoter analysis of the prtP gene revealed CcpA binding sites with high identity to the cre consensus sequence and the interaction of CcpA with this promoter was confirmed in vitro. We postulate that deregulation of the proteolytic system in BL71 allows a better exploitation of nitrogen resources in cheese whey, resulting in enhanced fermentation capacity. Therefore, the ccpA gene could be a good target for future technological developments aimed at effective and inexpensive lactate production from dairy industrial wastes.

Alternative Heterologous Expression of L-Arabinose Isomerase from Enterococcus faecium DBFIQ E36 By Residual Whey Lactose Induction.

This study reports an alternative strategy for the expression of a recombinant L-AI from Enterococcus faecium DBFIQ E36 by auto-induction using glucose and glycerol as carbon sources and residual whey lactose as inducer agent. Commercial lactose and isopropyl ß-D-1-thiogalactopyranoside (IPTG) were also evaluated as inducers for comparison of enzyme expression levels. The enzymatic extracts were purified by affinity chromatography, characterized, and applied in the bioconversion of D-galactose into D-tagatose. L-AI presented a catalytic activity of 1.67 ± 0.14, 1.52 ± 0.01, and 0.7 ± 0.04 U/mL, when expressed using commercial lactose, lactose from whey, and IPTG, respectively. Higher activities could be obtained by changing the protocol of enzyme extraction and, for instance, the enzymatic extract produced with whey presented a catalytic activity of 3.8 U/mL. The specific activity of the enzyme extracts produced using lactose (commercial or residual whey) after enzyme purification was also higher when compared to the enzyme expressed with IPTG. Best results were achieved when enzyme expression was conducted using 4 g/L of residual whey lactose for 11 h. These results proved the efficacy of an alternative and economic protocol for the effective expression of a recombinant L-AI aiming its high-scale production.

Effect of by-products from the dairy industry as alternative inducers of recombinant ß-galactosidase expression.

OBJECTIVE: The aim of the present study was to evaluate the efficiency of lactose derived from cheese whey and cheese whey permeate as inducer of recombinant Kluyveromyces sp. ß-galactosidase enzyme produced in Escherichia coli. Two E. coli strains, BL21(DE3) and Rosetta (DE3), were used in order to produce the recombinant enzyme. Samples were evaluated for enzyme activity, total protein content, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis after induction with isopropyl-ß-D-1-thiogalactoside (IPTG) (0.05 and 1 mM) and lactose, cheese whey, and cheese whey permeate solutions (1, 10, and 20 g/L lactose) at shake-flask cultivation, and whey permeate solution (10 g/L lactose) at bioreactor scale. RESULTS: The highest specific activities obtained with IPTG as inducer (0.05 mM) after 9 h of induction, were 23 and 33 U/mgprotein with BL21(DE3) and Rosetta(DE3) strains, respectively. Inductions performed with lactose and cheese whey permeate (10 and 20 g/L lactose) showed the highest specific activities at the evaluated hours, exhibiting better results than those obtained with IPTG. Specific activity of recombinant ß-galactosidase using whey permeate (10 g/L lactose) showed values of approximately 46 U/mgprotein after 24-h induction at shake-flask study, and approximately 26 U/mgprotein after 16-h induction at bench bioreactor. CONCLUSIONS: The induction with cheese whey permeate was more efficient for recombinant ß-galactosidase expression than the other inducers tested, and thus, represents an alternative form to reduce costs in recombinant protein production.

Lactose hydrolysis using ß-galactosidase from Kluyveromyces lactis immobilized with sodium alginate for potential industrial applications.

The present study aimed to evaluate the lactose hydrolysis conditions from "coalho" cheese whey using ß-galactosidase (ß-gal) produced by Kluyveromyces lactis immobilized with sodium alginate. Three sodium alginate-based immobilization systems were evaluated (0.5, 0.7, and 1% w/v) for maximizing the immobilization yield (Y), efficiency (EM), and recovered activity (ar). The lactose hydrolysis capacity of the immobilized form of ß-gal was determined, and simulated environments were used to assess the preservation of the immobilized enzyme in the gastrointestinal tract. The results showed that ß-gal immobilization with 1% (w/v) sodium alginate presented the best results (EM of 66%, Y of 41%, and ar of 65%). The immobilization system maintained the highest pH stability in the range between 5.0 and 7.0, with the highest relative activity obtained under pH 5 conditions. The temperature stability was also favored by immobilization at 50 °C for 30 min was obtained a relative activity of 180.0 ± 1.37%. In 6 h, the immobilized ß-gal was able to hydrolyze 46% of the initial lactose content. For the gastrointestinal simulations, around 40% of the activity was preserved after 2 h. Overall, the results described here are promising for the industrial applications of ß-galactosidase from K. lactis.

Effect of dairy by-products as milk replacers on quality attributes of ice cream.

The aim of this study was to evaluate the effect of ricotta whey (RW), cheese whey (CW), and butter whey (BUW) as replacers of whole milk (WM) at different ratios (0:100, 25:75, 50:50, 75:25, and 100:0) in the physicochemical and sensory qualities of ice cream. All formulations, including a commercial sample used as reference, were analyzed for nutritional composition, energy value, pH, titratable acidity (TA), melting behavior, desorption index, instrumental color properties, instrumental hardness, and consumer sensory testing. Overall, the addition of RW, CW, and BUW increased the moisture content, TA, melting rate, and redness (a*) and yellowness (b*) values but decreased the pH, lightness (L*) value, energy value, levels of ash, protein, lipid, and carbohydrate. As exception, CW did not influence the TA, and BUW resulted in lower lipid reduction and in lower hardness changes, and it did not affect the content of ash, protein, and a* and b* values of ice creams. Any ice cream formulation had dietary fibers and a desorption index. Ricotta whey and CW at all ratios and BUW at 25% did not affect overall liking compared with the commercial sample, whereas purchase intention was only decreased by the addition of BUW from 50 to 100%. Ricotta whey at 75 and 100% decreased melting velocity and creaminess, and BUW at 50, 75, and 100% increased hardness, TA, and cream flavor but decreased creaminess, which contributed negatively to overall liking. Therefore, the evaluated dairy by-products, especially RW and CW, have great potential for replacing milk in ice creams.

Potential of "coalho" cheese whey as lactose source for ß-galactosidase and ethanol co-production by Kluyveromyces spp. yeasts.

The present study evaluated the co-production of ß-galactosidase and ethanol by Kluyveromyces marxianus ATCC 36907 and Kluyveromyces lactis NRRL Y-8279 using as carbon source the lactose found on "coalho" cheese whey. Cheese whey was subjected to partial deproteinization, and physicochemical parameters were assessed. Cultivations were carried out in an shaker to evaluate two carbon/nitrogen (C:N) ratios. The best C:N ratio (1.5:1) was carried to 1.5-L bioreactor cultivation in order to increase co-production yields. The stability of ß-galactosidase was assessed against different temperatures and pH, and in the presence of metal ions. Concerning the co-production of ß-galactosidase and ethanol, K. lactis proved to be more efficient in both the C:N ratios, reaching 21.09 U·mL-1 of activity and 7.10 g·L-1 of ethanol in 16 h. This study describes the development of a viable and value-adding biotechnological process using a regional cheese by-product from Northeast Brazil for co-production of biomolecules of industrial interest.

High rate of biological removal of sulfate, organic matter, and metals in UASB reactor to treat synthetic acid mine drainage and cheese whey wastewater as carbon source.

The anaerobic biological treatment of sulfate-rich effluents, such as acid mine drainage (AMD), is mediated by sulfate-reducing bacteria (SRB). This process involves the reduction of sulfates in the presence of an electron donor. Complex carbon compounds can be used as electron donors. In the present study, was used an upflow anaerobic sludge blanket (UASB) reactor to co-treat a low-pH synthetic AMD and cheese whey wastewater (CWW). Were observed higher sulfate and COD removal rates (1,114 ± 88 and 1,214 ± 128 mg L-1  day-1 , respectively) at higher sulfate and applied COD loading rates (1,500 mg L-1  day-1 ). The overall pH of the effluent remained above 6.4 without any bicarbonate supplementation. Almost 100% of the Fe, Zn, and Cu was removed and the presence of metals improved the process. The use of a single reactor to treat AMD and CWW is promising. PRACTITIONER POINTS: Wastewater cheese whey was electron donor for treating acid mine drainage in an UASB reactor. Metals additions in the system indicated an increased removal of COD. About 99% of the metals were removed with the treatment.

Cheese whey permeate fermentation by Kluyveromyces lactis: a combined approach to wastewater treatment and bioethanol production.

Cheese whey is a dairy industry by-product responsible for serious environmental problems. Its fermentation would allow reducing its environmental impact and producing, at the same time, high-value products, hence ensuring cleaner production. Batch fermentations of cheese whey permeate, either as such or 1.5-fold or twice-concentrated, by Kluyveromyces lactis CBS2359 were performed in flasks with or without agitation to select the best conditions to produce simultaneously ethanol and biomass with high ß-galactosidase activity. In shake cultures, the highest ethanol concentration (15.0 g L-1), yield on consumed lactose (0.47 g g-1) and productivity (0.31 g L-1 h-1), were obtained on cheese whey permeate as such, corresponding to 87.4% fermentation efficiency, but ß-galactosidase activity was disappointing (449.3-680.0 U g-1). In static cultures on twice-concentrated whey permeate, despite a decrease in fermentation efficiency and yield, ethanol production increased by 48% and ß-galactosidase activity by no less than 209-367%. Therefore, cheese whey should be considered an alternative feedstock rather than an undesirable dairy industry by-product.

Controlling methane and hydrogen production from cheese whey in an EGSB reactor by changing the HRT.

This study assessed the effects of hydraulic retention time (HRT; 8 h-0.25 h) on simultaneous hydrogen and methane production from cheese whey (5000 mg carbohydrates/L) in a mesophilic (30 °C) expanded granular sludge bed (EGSB) reactor. Methane production was observed at HRTs from 4 to 0.25 h. The maximum methane yield (9.8 ± 1.9 mL CH4/g CODap, reported as milliliter CH4 per gram of COD applied) and methane production rate (461 ± 75 mL CH4/day Lreactor) occurred at HRTs of 4 h and 2 h, respectively. Hydrogen production increased as methane production decreased with decreasing HRT from 8 to 0.25 h. The maximum hydrogen yield of 3.2 ± 0.3 mL H2/g CODap (reported as mL H2 per gram of COD applied) and hydrogen production rate of 1951 ± 171 mL H2/day Lreactor were observed at the HRT of 0.25 h. The decrease in HRT from 8 to 0.25 h caused larger changes in the bacterial populations than the archaea populations. With the decrease in HRT (6 h-0.25 h), the Shannon diversity index decreased (3.02-2.87) for bacteria and increased (1.49-1.83) for archaea. The bacterial dominance increased (0.059-0.066) as the archaea dominance decreased (0.292-0.201) with the HRT decrease from 6 to 0.25 h.

Production of Antioxidant and ACEI Peptides from Cheese Whey Discarded from Mexican White Cheese Production.

Cheese whey, a byproduct of the cheese-making industry, is discarded in many countries in the environment, causing pollution. This byproduct contains high-quality proteins containing encrypted biologically active peptides. The objective of this work was to evaluate the suitability of using this waste to produce bioactive peptides by enzymatic hydrolysis with a digestive enzyme. Cheese whey from white cheese (Panela cheese) was concentrated to increase total protein and hydrolyzed with trypsin. A central composite design was used to find the best conditions of pH and temperature, giving the higher antioxidant capacity and Δ Angiotensin-converting enzyme inhibition (Δ ACEI) activity. Higher biological activities were found when hydrolysis was performed at 52 °C and a pH of 8.2. The maximum value for the 2,2- diphenyl-1-picrylhydrazyl (DPPH)-scavenging activity was 26%, while the higher Δ ACE inhibition was 0.89. Significant correlations were found between these biological activities and the peptides separated by HPLC. The hydrophilic fraction (HI) showed highly significant correlations with the antioxidant capacity (r = 0.770) and with Δ ACE inhibition (r = 0.706). Antioxidant capacity showed a significant positive correlation with 34 peaks and Δ ACE inhibition with 33 peaks. The cheese whey was successfully used as raw material to produce peptides showing antioxidant capacity and ACEI activity.

Safety, functional properties and technological performance in whey-based media of probiotic candidates from human breast milk.

We aimed at isolating and characterising microorganisms present in human breast milk with probiotic potential. In an 8-week postpartum sampling period, two strains of bifidobacteria (Bifidobacterium longum LM7a and Bifidobacterium dentium LM8a') and four strains of lactobacilli were isolated, all during the first 4-week postpartum. B. longum LM7a and B. dentium LM8a', together with four strains previously isolated from breast milk (Bifidobacterium lactis INL1, INL2, INL4 and INL5), were considered for further studies. Susceptibility of the strains to tetracycline, erythromycin, clindamycin, streptomycin, vancomycin and chloramphenicol was evaluated and the isolates exhibited, in general, the same properties as previously reported for bifidobacteria. All isolates showed low hydrophobicity and B. lactis and B. longum strains had satisfactory resistance to gastric digestion and bile shock, but not to pancreatin. B. lactis INL1, B. longum LM7a and B. dentium LM8a' were selected for some comparative technological studies. In particular, B. lactis INL1 displayed technological potential, with satisfactory growth in cheese whey-based media in biofermentor and resistance to freeze-drying, accelerated storage conditions and simulated gastric digestion.

Produção de ácido cítrico por Aspergillus niger AN 400 a partir de resíduo agroindustrial / Citric acid production by Aspergillus niger AN 400 from agroindustry waste

RESUMO A agroindústria gera grandes volumes de resíduos com carga poluidora elevada, o que exige o desenvolvimento de tecnologias para minimização de impactos causados pela disposição inadequada desses resíduos no ambiente. A produção de ácido cítrico utilizando resíduos agroalimentares como substrato para fermentação é uma solução para a redução da carga orgânica desses poluentes, além de agregar valor econômico pela geração de produto rentável. Aspergillus niger AN 400 foi utilizado para produzir ácido cítrico a partir de soro de queijo. A pesquisa foi dividida em três fases, conforme adição de açúcar extra (50, 100 e 150 g.L-1): Fase I, com glicose; Fase II, com sacarose; e Fase III, apenas com o soro de queijo, sem adição extra de açúcar. Os reatores permaneceram sob agitação de 150 rpm e a 30ºC, por 10 dias. A maior concentração de ácido cítrico (2.379 mg.L-1) foi observada quando da adição de 100 g.L-1 de glicose. Porém, em termos de produtividade, os maiores valores foram registrados nos reatores com 50 (458 mg.L-1.dia-1) e 100 g.L-1 (745 mg.L-1.dia-1) de sacarose, seguido pelo reator que continha apenas soro de queijo, sem adição de açúcar extra (313 mg.L-1.dia-1), demonstrando o potencial desse resíduo para a obtenção desse ácido de grande interesse comercial.

ABSTRACT The agro-industry generates large volumes of waste with high organic load, which requires the development of technologies to minimize the impacts caused by the improper disposal of this waste on the environment. The citric acid produced by agro food wastes as substrate for fermentation is a solution to reduce the organic load of these pollutants and add economic value by generating a profitable product. Aspergillus niger AN 400 was used to produce citric acid from cheese whey. The study was divided in three phases according to the addition of extra sugar (50, 100, 150 g.L-1): Phase I, with glucose; Phase II, with sucrose, and Phase III, with cheese whey only, without adding extra sugar. The reactors remained under agitation 150 rpm and at 30ºC for 10 days. The highest concentration of citric acid (2,379 mg.L-1) was observed upon the addition of 100 g.L-1 of glucose. However, the greatest yields were recorded in the reactors with 50 (458 mg.L-1.day-1) and 100 g.L-1 (745 mg.L-1. day-1) of sucrose, followed by the reactor that contained only cheese whey, without adding extra sugar (313 mg.L-1.day-1), demonstrating the potential of this waste to obtain citric acid with a great commercial interest.

Production of Propionic Acid by Propionibacterium acidipropionici from Agroindustrial Effluents

Abstract The purpose of this paper was to evaluate the production of propionic acid from the fermentation of agroindustrial effluents using a Propionibacterium acidipropionici culture. The composition of the substrates was determined by using an experimental design of mixtures, resulting in 10 trials. The substrates were fermented in batch borosilicate glass reactors at a temperature of 35°C, initial pH of 6.5, and 20 mL.L-1 of inoculum suspension. The highest yield of propionic acid production, 0.79 g of product per g of substrate, was obtained with a substrate composed only of corn steep liquor, which showed a productivity of 5.20 mg.L-1h-1 and production of 0.40mL.L-1. These results showed that the corn steep liquor positively influenced performance and productivity. Although the production of acid did not reach high values, the results indicate that it is possible to produce propionic acid by a biotechnological route; however, further studies are required to adapt and optimise these results.

Enhanced Bacteriocin Production by Pediococcus pentosaceus 147 in Co-culture With Lactobacillus plantarum LE27 on Cheese Whey Broth.

The production of bacteriocins by lactic acid bacteria (LAB) has been of wide interest in the food industry due to their potential application in biopreservation. The production of bacteriocins is usually low in single strain fermentation, but can improve when the bacteriocinogenic strain is cultured in association with another bacteria. The present work aims to evaluate the growth and production of bacteriocins by Pediococcus pentosaceus 147 (bacteriocinogenic strain) in co-culture with Lactobacillus plantarum LE27 (inducer strain) using a culture medium based on cheese whey (CW). Strains were inoculated in co-culture in a CW broth at 7.24 Log CFU/mL of initial concentration of P. pentosaceus 147 and incubated at 37°C. Bacteriocin production was measured after 24 h by the critical dilution method, biomass was measured by plating on MRS agar (1% aniline blue), and a mono-culture was used as a control. The titers of bacteriocins produced by P. pentosaceus 147 in mono-culture were 19,200 AU/mL lower than those obtained in co-culture with Lb. plantarum LE27 at 51,200 AU/mL. The effect of adding the inducer strain at different times of incubation (3, 6, 9, and 12 h) was evaluated, with the addition of the induction factor at the beginning of the incubation of P. pentosaceus 147 generating the highest bacteriocin activity. This study shows the potential of inducing bacteriocinogenesis using co-cultures of strains of the genera Pediococcus and Lactobacillus and using alternative substrates such as cheese whey.

Development of alginate-pectin microparticles with dairy whey using vibration technology: Effects of matrix composition on the protection of Lactobacillus spp. from adverse conditions.

In this study, lactic acid bacteria with probiotic potential, including Lactobacillus plantarum ATCC8014, L. paracasei ML33 and L. pentosus ML82, were encapsulated with whey-alginate-pectin (WAP) or whey permeate-alginate-pectin (PAP) by an extrusion process using vibrational technology, with the resulting microparticles assessed for their resistance to adverse conditions. The aim was to assess the effect of the encapsulation wall materials on the viability of microorganisms, the encapsulation, refrigerated storage and simulated gastrointestinal tract conditions, the kinetic parameters of acidification, and the morphology of microparticles. The bacteria encapsulated with the WAP wall material were adequately protected. Furthermore, after three months of storage at 4 °C, the encapsulated bacteria exhibited a cell viability of >6 log CFU mL-1. In addition, the encapsulated L. plantarum ATCC8014 and L. pentosus ML82 isolates exhibited the highest viability at the end of the storage period among the assayed isolates. Encapsulated bacteria showed greater resistance to acidic conditions than unencapsulated bacteria when exposed to simulated gastrointestinal tract conditions. The maximum rate of milk acidification by encapsulated Lactobacillus spp. was approximately three-fold lower than that observed for unencapsulated bacteria. The resulting size of the microparticles generated using both combinations of wall materials used was approximately 150 µm. The cheese whey and whey permeate combined with alginate and pectin to adequately encapsulate and protect Lactobacillus spp. from the adverse conditions of the simulated gastrointestinal tract and from refrigeration storage temperatures. Furthermore, the sizes of the obtained microparticles indicated that the encapsulated materials are suitable for being incorporated into foods without changing their sensory properties.